5 g ground dates spiked with pesticides at 10 ng/g
add 10 mL water and 10 mL acetonitrile; shake 1 hr at 2500 rpm; add contents of Supel QuE citrate extraction tube (55227-U); . (shake for 1 minute; centrifuge at 5000 rpm fo 5 minutes and draw off supernatant)
Supel QuE PSA/C18 (55288-U)
transfer 1 mL of the extract to 2 mLSupel QuE PSA/C18 tube; shake for 1 minute; centrifuge at 5000 rpm for 3 min; draw off supernatant for analysis.
Dilute 100 μL of cleaned extract to a final volume of 1 mL in 5 mM ammonium formate/0.1% formic acid in water; transfer diluted sample to vial for LC/MS/MS analysis
Ascentis Express RP-Amide, 10 cm x 2.1 mm I.D., 2 μm particles (51576-U)
(A) 5 mM ammonium formate with 0.1% formic acid in water; (B) 5 mM ammonium formate with 0.1% formic acid in 95:5 acetonitrile:H2O
held at 5% B from 0 to 1 min; to 100% B in 13 min; held at 100% B for 1.5 min; to 95% A in 0.5 min; held at 95% A for 1.5 min
0.4 mL/min
30 °C
MS, ESI (+), MRM
5 μL
Freeze dates with liquid nitrogen and grind to a homogenous mixture.
The “quick, easy, cheap, effective, rugged, and safe” (QuEChERS) method can be used to analyze multiple pesticide residues found in dates. In this study, QuEChERS extraction and cleanup using PSA/C18 were used for the analysis of pesticide residues of interest in pistachios. Average recoveries obtained for replicate samples spiked at 10 ng/g were in the range of 70-120% for 23 of the 25 pesticides analyzed.
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